NEW YORK — Almost three months after the birth of Tom Cruise and Katie Holmes’ daughter, the Shroud of Suri has yet to be lifted.

Suri Cruise has yet to be seen in public, either in person or photographically, since entering the world April 18.

To some, this is a holdout of staggering proportions.

Us Weekly magazine is running a clock, ticking off the days (84 and counting) since Suri’s birth. German TV station RTL, taking matters into its own hands, has produced a composite image of what Suri might look like. TMZ.com, perhaps digging for evidence of Suri’s existence, obtained a copy of the official birth certificate, filed May 8 in Los Angeles. And gossip Web site Defamer.com has called the delay “profoundly strange” and upgraded its suspicion from “mystery” to “riddle that would make the Sphinx incontinent.”

Lest anyone rent out milk-carton space, Cruise spokesman Arnold Robinson pleads for privacy: “If and when they do make a decision, it will be at their discretion and not anybody else’s,” he told The Associated Press.

The secrecy is in stark contrast to the couple’s radically public courtship. Cruise, 44, and Holmes, 27, spared no photo-op during their whirlwind romance. They are now engaged, though there has been no word on wedding plans.

The top Invisible Baby theory involves Cruise’s Scientology beliefs. The religion’s founder, L. Ron Hubbard, was very specific about how infants should be treated, and taught that birth should occur in a silent environment.

Meanwhile, other celebrity babies born since Suri have made their public bows. The daughter of Brooke Shields and Chris Henchy, Grier Hammond Henchy, was revealed weeks ago — and she was born the same day as Suri. Brad Pitt and Angelina Jolie’s daughter, Shiloh Nouvel, was born on May 27 and landed in several magazines by early June. The recently born children of Gwen Stefani and Rachel Weisz are confirmed to exist.

But Suri remains unseen, which is not unusual for a Cruise child. When he and Nicole Kidman were married, their two adopted children weren’t photographed until 1996, when son Conor Anthony was a year old and daughter Isabella Jane was 3.

Given that track record, those counting clocks might still have a while to tick.